Computer networks, connections and protocols

Question 1

internet

Answer 1

the collection of inner connected networks. many services make use of the internet such as the WWW

Question 2

WWW (World Wide Web)

Answer 2

one of the services that makes use of the internet. it is the information system of interlinked web pages and other resources. it is accessed rom a web browser and makes use of HTTP to send and receive data

Question 3

WAN (Wide Area Network)

Answer 3

large geographical area. any network in which the computers communicate using resources supplied by a third party carrier such as BT. it uses cables, telephone lines and satellites to connect two or more remote locations. the internet is the largest wide area network in the world

Question 4

Circuit switching network

Answer 4

when a telephone call is made, a dedicated connection is set up between the two people calling for the duration of the call.
it is good enough to make phone calls but there could never be enough lines for all the billions of people sending data across the internet

Question 5

packet switching

Answer 5

packet switching is a method of grouping data into short messages (packets) with a header and a payload
each packet is given a header

1. the IP address it is going to
2. the IP address it has come from
3. the sequence number of the packet
4. the number of packets in the whole communication
5. error checking data

Question 6

Data packets

Answer 6

1. each data packet will contain the same number of bytes
2. the packets may flow through the internet via different routes
3. each packet is marked with the packet number so that the packets can be put back together by the receiver

Question 7

reassembling data

Answer 7

1. the recipient computer re-orders the packet into the correct order
2. each packet is checked for errors
3. corrupt packets are requested to be resent

Question 8

Moving packets on the net

Answer 8

points of a network diagram are called nodes
routers are any node that can route packets from one place to another

Question 9

DNS (domain name system)

Answer 9

1. it translates human friendly computer hostnames into IP addresses
2. there are 13 DNS servers worldwide which keep a complete database of all domain names and IP addresses
3. when a DNS server receives a request not in its database it will pass the request on to another server until it reaches one with the matching name and IP address

Question 10

NIC (network interface card)

Answer 10

it is built into every networked device, it may be wireless with an antenna or wired with a network cable

Question 11

MAC address (media access control)

Answer 11

it is assigned to each network interface card by the manufacturer

Question 12

IP address (Internet protocol)

Answer 12

every computer in the world has an IP address
there are two types of IP addresses IPV4 and IPV6

Question 13

LAN (Local area network)

Answer 13

A LAN operates on a single site such as a school, hotel or business. it covers a small geographical area.

Question 14

Switch

Answer 14

a switch sends data to the appropriate connected computers.

Question 15

Router

Answer 15

It routes packets of data towards their destination.

Question 16

Hub

Answer 16

A hardware device that enables multiple devices or connections to connect to a computer.

Question 17

Advantages and disadvantages of networks

Answer 17

Advantages -
Computers can share resources
Files can be accessed through any computer in the network.
Data is easy to back as it is stored centrally on the server.

Disadvantages -
Purchasing the network hardware is expensive.
Managing a large network is complicated
Viruses may be able to infiltrate the network and infect other devices.

Question 18

Network topologies

Answer 18

A topology is the way in which parts of a system are connected.
there are two types of topologies
- Star
- Mesh